Coil structure of a test platform

Abstract

The present invention belongs to the field of production, manufacturing and testing of converter transformers, and specifically relates to a coil structure of a test platform. The test platform is applied to converter transformers. The coil structure includes a bottom end ring, a valve side coil and a grid side coil. The bottom end ring, the valve side coil and the grid side coil are arranged on the outer periphery of the iron core, and the valve side coil is arranged between the iron core and the grid side coil. The valve side coil and the grid side coil are placed on the upper surface of the bottom end ring; the valve side coil and the grid side coil have the same structure, and both include a coil lower end ring located at the lower bottom end of the valve side coil and the grid side coil. When it is necessary to replace the test platform coil of different forms during the test process, only the bottom end ring needs to be hoisted to replace the entire test platform coil, or the valve side coil and the grid side coil can be separately hoisted and replaced through the coil lower end rings. The coil structure of the present invention can be hoisted as a whole, has good integrity, is tightly wound, has a simple structure, and is simple and convenient to hoist when the coils of different forms are interchanged.

Description

Technical Field

[0001] The invention belongs to the technical field of production, manufacturing and testing of converter transformers, and particularly relates to a coil structure of a test platform, and the test platform is applied to converter transformers. Background Art

[0002] A converter transformer is one of the core devices of a high-voltage direct-current power transmission system. During operation, the converter transformer is subjected to the combined action of alternating and direct current voltages. A large number of high-order harmonics and DC bias magnetic currents are contained in its load current. These currents flow through the windings of the converter transformer, causing the windings to be subjected to complex electromagnetic forces. Coupled with the magnetostrictive effect existing in the iron core itself, the vibrations of the iron core and windings are very complex. The vibrations of the iron core and windings are transmitted to the surface of the oil tank through the box structure, triggering more complex vibrations and noises of the entire converter transformer, thus threatening the safe operation of the converter transformer.

[0003] The problem of vibration and noise of the converter transformer affects the service life of the converter transformer on the one hand and is prone to cause accidents. On the other hand, the noise radiation generated by the converter transformer affects the physical health of employees and causes noise pollution to the living and working environments of surrounding residents. Therefore, it is urgent to conduct in-depth and systematic research in this field. To conduct vibration and noise research, a test platform for converter transformers needs to be built. On this test platform, coils of different structural forms are frequently disassembled, assembled and replaced for vibration and noise tests. For the current conventional coil structure, after the coil winding is completed, the shielding and spacers are assembled. When the coil of the converter transformer test platform needs to be frequently disassembled and replaced, the shielding and spacers must be removed first, and then the coil is replaced. Therefore, the existing coil structure cannot well meet the operation requirements of the test platform coil that needs to be frequently disassembled and assembled, and a new type of test platform coil structure needs to be designed. Summary of the Invention

[0004] In order to solve the above technical problems, the invention provides a coil structure of a test platform. The technical solution adopted by the invention is as follows:

[0005] A coil structure of a test platform, the test platform is applied to a converter transformer, and the coil structure includes: a bottom end ring, a valve side coil and a line side coil. The bottom end ring, the valve side coil and the line side coil are all sleeved on the outer periphery of the iron core. The valve side coil and the line side coil are placed on the upper surface of the bottom end ring, and the valve side coil is sleeved between the iron core and the line side coil; the valve side coil and the line side coil have the same structure, and both the valve side coil and the line side coil include a coil lower end ring placed at the lower bottom end.

[0006] When different forms of test platform coils need to be replaced during the test process, the bottom end ring is used for the overall hoisting of the test platform coils during disassembly, assembly and combination. Only by hoisting the bottom end ring can the entire test platform coil be replaced. At the same time, the valve side coil and the line side coil can also be separately hoisted and replaced through the lower end rings of the coils. As the lower positioning support of the test platform coil, the structures of the bottom end ring and the lower end rings of the coil meet the process requirements for the overall hoisting and sleeving of the test platform coil.

[0007] Preferably, both the valve side coil and the line side coil include: hanging spacer bars and a hard paper tube. The hard paper tube is used to be sleeved and fixed on the outer periphery of the winding mold, and the lower end of the hard paper tube is located at the inner diameter edge position of the upper surface of the lower end ring of the coil. A number of hanging spacer bars are fixedly installed at intervals on the outer periphery of the hard paper tube away from the winding mold; a lower end ring of the conductor is sleeved on the lower outer periphery of the hanging spacer bar. The lower end ring of the conductor is located on the upper surface of the lower end ring of the coil. A number of oil duct spacer blocks are fixedly installed on the upper surface of the lower end ring of the conductor to form a bottom layer oil duct spacer block ring. Multilayer paper-covered flat conductors are wound around the outer periphery of the hanging spacer bars above the bottom layer oil duct spacer block ring. A number of oil duct spacer blocks are fixedly arranged between any two adjacent layers of paper-covered flat conductors. A number of oil duct spacer blocks are fixedly installed on the upper surface of the top layer paper-covered flat conductor to form a top layer oil duct spacer block ring. An upper end ring of the conductor is sleeved on the upper outer periphery of the hanging spacer bar. The upper end ring of the conductor is located on the upper surface of the top layer oil duct spacer block ring.

[0008] Preferably, both the valve side coil and the line side coil further include: a number of coil outer support bars, a number of layers of shielding and oil duct support bars. The coil outer support bars are fixedly installed on the outer periphery of the upper end ring of the conductor, multilayer paper-covered flat conductors, multilayer oil duct spacer blocks and the lower end ring of the conductor. A number of layers of shielding and oil duct support bars are sleeved on the outer periphery of a circle of coil outer support bars. The lower ends of the shielding and oil duct support bars are located on the upper surface of the lower end ring of the coil.

[0009] Preferably, the lower end ring of the coil includes an upper spacer block, a paper ring and a lower spacer block. The upper spacer block and the lower spacer block are aligned and adhesively bonded to the upper surface and the lower surface of the paper ring respectively.

[0010] Preferably, the outer peripheral edges of the upper end ring of the conductor and the lower end ring of the conductor are provided with first slots. Vertical through holes are opened in the height direction of the lower end ring of the coil. Second slots are arranged at intervals along the width direction of the coil outer support bar on the coil outer support bar. The PET tape passes through the second slots and binds the coil outer support bar in the circumferential direction.

[0011] Preferably, the cross section of the hanging spacer bar is T-shaped, and the edge positions are rounded; the radial cross sections of the upper end ring of the conductor and the lower end ring of the conductor are rectangular cross sections, and the edge positions are rounded.

[0012] Preferably, the transverse cross section of the oil duct support bar is a rectangular cross section, and the rectangular corners are rounded.

[0013] Preferably, the materials of the cardboard tube, the surrounding screen, the hanging spacer support bar, the coil outer support bar, and the oil duct support bar are insulating cardboard.

[0014] Preferably, the materials of the upper end coil of the wire and the lower end coil of the wire are laminated cardboard.

[0015] Preferably, the materials of the upper spacer, the paper ring, and the lower spacer are laminated cardboard, and the edges of the upper spacer and the lower spacer are rounded.

[0016] The beneficial effects of the present invention are as follows:

[0017] For the coil structure of a test platform of the present invention, the bottom end coil is placed at the lowermost part, and the lower end coils of the valve side coil and the line side coil are placed below, realizing the overall hoisting of the coil; the oil duct spacers are added between turns in the height direction, which can adjust the overall height of the coil, being beneficial to heat dissipation and ampere-turn balance; the outer support bars of the coil are tied with PET tapes, which can effectively increase the seismic resistance of the coil; the coil structure has good integrity, is tightly wound, and has a simple structure. When coils of different forms are interchanged, the process hoisting is simple and convenient, which can reduce the air exposure time of components such as the iron core and the body during the test, reduce the total idle time, and provide effective support for the vibration mechanism test research of coils with different structural forms. Description of the Drawings

[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some specific embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings belonging to the scope of protection of this application can also be obtained based on these drawings.

[0019] Figure 1 It is a schematic diagram of the overall structure of the coil structure of the test platform according to an embodiment of the present invention;

[0020] Figure 2 It is a structural cross-sectional view of the valve side coil and the line side coil according to an embodiment of the present invention;

[0021] Figure 3-1 It is a schematic diagram of the structure of the cardboard tube according to an embodiment of the present invention;

[0022] Figure 3-2 It is a top view of the cardboard tube according to an embodiment of the present invention;

[0023] Figure 4-1 It is a schematic diagram of the structure of the coil outer support bar according to an embodiment of the present invention;

[0024] Figure 4-2It is the right view of the coil outer support bar of the embodiment of the present invention;

[0025] Figure 5 It is the structural schematic diagram of the upper end coil of the wire of the embodiment of the present invention;

[0026] Figure 6-1 It is the structural schematic diagram of the lower end coil of the coil of the embodiment of the present invention;

[0027] Figure 6-2 It is of the embodiment of the present invention Figure 6-1 The sectional view at N-N of;

[0028] Figure 7 It is the process flow chart of the machining of the coil structure of the test platform of the embodiment of the present invention;

[0029] In the figure, 1 is the bottom end coil, 2 is the iron core, 3 is the valve side coil, 4 is the line side coil, 5 is the winding die, 6 is the hard paper tube, 7 is the hanging pad support bar, 8 is the upper end coil of the wire, 9 is the paper-covered flat wire, 10 is the oil duct pad, 11 is the coil outer support bar, 12 is the shielding screen, 13 is the oil duct support bar, 14 is the lower end coil of the coil, 15 is the upper pad, 16 is the paper ring, 17 is the lower pad, 18 is the lower end coil of the wire. Detailed implementation manners

[0030] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments.

[0031] As Figure 1 shown, it is the overall schematic diagram of the coil structure of the test platform of the embodiment of the present invention. A coil structure of a test platform includes: a bottom end coil 1, a valve side coil 3 and a line side coil 4 sleeved on the outer periphery of the iron core 2, forming an overall coil structure of the test platform for frequent disassembly and assembly. The valve side coil 3 and the line side coil 4 are placed on the upper surface of the bottom end coil 1, and the valve side coil 3 is sleeved between the iron core 2 and the line side coil 4, which can realize the simultaneous replacement of the two coils of the valve side coil 3 and the line side coil 4, or the separate replacement of the valve side coil 3 or the line side coil 4.

[0032] As Figure 2 shown, it is the structural sectional view of the valve side coil and the line side coil of the embodiment of the present invention. The valve side coil 3 and the line side coil 4 are both cylindrical structures as a whole, Figure 2They are only partial sectional views on one side of them, not their complete structures. The valve-side coil 3 and the line-side coil 4 each include: a hard paper tube 6, a hanging pad support bar 7, a paper-covered flat wire 9, a coil outer support bar 11, a shielding screen 12, an oil duct support bar 13, a lower end coil 14 of the coil, an upper end coil 8 of the wire, a lower end coil 18 of the wire, and an oil duct pad 10. The lower end coil 14 of the coil is located at the lower bottom end of the valve-side coil 3 and the line-side coil 4. A vertical through hole (shown by the dotted line in Figure 2 ) is provided in the height direction of the lower end coil 14 of the coil. The vertical through hole is used to lead out the lower end of the paper-covered flat wire 9. The hard paper tube 6 is sleeved on the outer periphery of the winding mold 5, and the lower end of the hard paper tube 6 is located at the inner diameter edge position of the upper surface of the lower end coil 14 of the coil. A plurality of hanging pad support bars 7 in the vertical direction are fixedly bonded to the outer periphery of the hard paper tube 6 at intervals by glue. A plurality of hanging pad support bars 7 are fixedly installed at intervals on the outer periphery of the hard paper tube 6 away from the winding mold 5. The lower outer periphery of the hanging pad support bar 7 is sleeved with a lower end coil 18 of the wire. The lower end coil 18 of the wire is located on the upper surface of the lower end coil 14 of the coil. A plurality of oil duct pads 10 are fixedly installed on the upper surface of the lower end coil 18 of the wire to form a bottom layer of oil duct pads. The outer periphery of the hanging pad support bar 7 above the bottom layer of oil duct pads is wound with multiple layers of paper-covered flat wires 9. A plurality of oil duct pads 10 are fixedly provided between any adjacent two layers of paper-covered flat wires 9. A plurality of oil duct pads 10 are fixedly installed on the upper surface of the top layer of paper-covered flat wires 9 to form a top layer of oil duct pads. The upper outer periphery of the hanging pad support bar 7 is sleeved with an upper end coil 8 of the wire. The upper end coil 8 of the wire is located on the upper surface of the top layer of oil duct pads. The hanging pad support bar 7 is a long strip structure. The cross section of the hanging pad support bar 7 is T-shaped. When bonding, the outer side of the vertical wide side of the T-shaped cross section of the hanging pad support bar 7 is bonded to the outer periphery of the hard paper tube 6. The protruding vertical edge perpendicular to the wide side is inserted into the oil duct pad 10. One side of the oil duct pad 10 is grooved and hung on the hanging pad support bar 7. The edge position of the hanging pad support bar 7 is rounded at the periphery without sharp corners and burrs to protect the paper-covered flat wire 9.

[0033] The valve-side coil 3 and the line-side coil 4 also each include: a plurality of coil outer support bars 11, and a plurality of layers of shielding screens 12 and oil duct support bars 13. The coil outer support bars 11 are fixedly installed on the outer peripheries of the upper end coil 8 of the wire, multiple layers of paper-covered flat wires 9, multiple layers of oil duct pads 10, and the lower end coil 18 of the wire. A plurality of layers of shielding screens 12 and oil duct support bars 13 are sleeved on the outer periphery of a circle of coil outer support bars 11. The lower ends of the shielding screens 12 and the oil duct support bars 13 are located on the upper surface of the lower end coil 14 of the coil. The structures of the valve-side coil 3 and the line-side coil 4 are the same, except that the number of layers of the shielding screen 12 - oil duct support bar 13 - shielding screen 12 - oil duct support bar 13 is different.

[0034] As Figure 3-1 shown, it is a schematic structural diagram of the hard paper tube according to an embodiment of the present invention; as Figure 3-2As shown in the figure, it is a top view of the hard paper tube according to an embodiment of the present invention. The hard paper tube 6 is made by winding and splicing 100 / 00 type insulating cardboard. Ramps that match each other are made at the edge positions of the overlapping parts of the insulating cardboard, and glue is applied at the ramps for shaping to ensure that there are no air bubbles at the overlapping parts where glue is applied, and the overlapping parts are preferably bonded to the hanging pad support bar 7.

[0035] In the valve-side coil 3 and the line-side coil 4, a single-conductor continuous-turn structure is used to wind the paper-covered flat wire 9 around the outer circumference of the hanging pad support bar 7. When winding the paper-covered flat wire 9, the winding mold 5 is placed at the winding station to adjust the diameter, and the winding mold 5 is located inside the hard paper tube 6. One layer of oil duct spacer 10 is placed for each layer of the paper-covered flat wire 9 wound. The paper-covered flat wire 9 is transposed at the layer-ascending position, and insulating paper is wrapped at the transposition position. The insulating paper is half-lapped and wrapped in two layers. The transposition position refers to the position where the paper-covered flat wire 9 transitions from one layer of wire (one layer) to the next layer of wire (the next layer). Wrapping the insulating paper is to increase the protection of the paper-covered flat wire 9 at the transposition position. The paper-covered flat wire 9 is wound into a continuous-turn structure (including but not limited to this structure) to serve as the main body of the valve-side coil 3 and the line-side coil 4.

[0036] After the paper-covered flat wire 9 is wound with the corresponding designed number of turns, the upper wire end coil 8 is placed on the upper part. After drying and pressing, the height of the coil is adjusted through the oil duct spacer 10. The coil outer support bar 11 is placed on the outer circumference of the paper-covered flat wire 9. After tying the PET tape, according to the insulation distance between the line-valve coils (the valve-side coil 3 and the line-side coil 4) - the size of the main air duct, in accordance with the thin paper tube and small oil gap theory, the shielding screens 12 - oil duct support bars 13 - shielding screens 12 - oil duct support bars 13 - shielding screens 12 - oil duct support bars 13 are placed in sequence and fixed along the circumferential direction with a white cloth tape, waiting for the next process of sleeving. The cross-section of the oil duct support bar 13 is a rectangular cross-section, and the rectangular corners are rounded. Through the oil duct spacer 10, it is convenient to adjust the height of the valve-side coil and form a heat dissipation oil duct for heat dissipation.

[0037] As Figure 4-1 shown, it is a schematic structural view of the coil outer support bar according to an embodiment of the present invention; as Figure 4-2 shown, it is a right view of the coil outer support bar according to an embodiment of the present invention. Second slots are spacedly opened in the width direction of the coil outer support bar 11. After the valve-side coil is wound and pressed and the height is adjusted, the coil outer support bar 11 is placed, and the PET tape is passed through the second slots and wound around three layers along the circumferential direction for tying, which can enhance the mechanical strength and seismic resistance of the valve-side coil and improve the short-circuit resistance.

[0038] As Figure 5As shown in the figure, it is a schematic structural diagram of the upper end coil of the wire in the embodiment of the present invention. The structure of the lower end coil 18 of the wire is the same as that of the upper end coil 8 of the wire. Both the upper end coil 8 and the lower end coil 18 of the wire are continuous end coils, and the radial cross-section is a rectangular cross-section. The edges of the upper end coil 8 and the lower end coil 18 of the wire are rounded. The rounding can protect the paper-covered flat wire 9. A first slot is opened at the outer peripheral edge of the upper end coil 8 and the lower end coil 18 at the position corresponding to the lead-out of the valve-side coil 3. The first slot can facilitate the lead-out of the head of the paper-covered flat wire 9 after adding the insulating paper, and at the same time ensure the uniform electric field at the upper and lower ends of the valve-side coil. The upper lead-out (head) of the grid-side coil 3 passes through the first slot of the upper end coil 8 of the wire and is connected to the grid bushing, and the lower lead-out (tail) passes through the first slot of the lower end coil 18 of the wire and the vertical through-hole of the lower end coil 14 of the coil and is connected to the grid neutral point bushing; the upper lead-out of the valve-side coil 4 is connected to the valve-side bushing a, and the lower lead-out is connected to the valve-side bushing b.

[0039] As Figure 6-1 shown, it is a schematic structural diagram of the lower end coil of the coil in the embodiment of the present invention; as Figure 6-2 shown, it is the Figure 6-1 cross-sectional view at N-N of the embodiment of the present invention. The lower end coil 14 of the coil includes an upper spacer 15, a paper coil 16, and a lower spacer 17. The upper spacer 15 and the lower spacer 17 are aligned with each other and bonded to the upper surface and the lower surface of the paper coil 16 respectively. The number of the upper spacer 15 and the lower spacer 17 is the same as the number of grading of the valve-side coil, ensuring the smooth flow of oil. At the same time, when the valve-side coil is sleeved and hoisted, it can have sufficient support strength. The lower end coil 14 is placed at the lowermost part of the valve-side coil 3 as a lower positioning support structure, and the overall hoisting and sleeving process of the valve-side coil 3 can be ensured, and disassembly and assembly combination can be carried out frequently.

[0040] The materials of the hard paper tube 6, the shielding screen 12, the hanging spacer support bar 7, the coil outer support bar 11, and the oil duct support bar 13 are all 100 / 00 type insulating cardboard.

[0041] The materials of the upper end coil 8 and the lower end coil 18 of the wire are both laminated cardboard.

[0042] The materials of the upper spacer 15, the paper coil 16, and the lower spacer 17 are all laminated cardboard. The upper spacer 15 and the lower spacer 17 have no sharp corners and burrs, and the edges are rounded.

[0043] As Figure 7 shown, it is a flow chart of the processing steps of the coil structure of the test platform in the embodiment of the present invention. The specific implementation steps are as follows:

[0044] Step 1. The lower end coil of the coil includes an upper spacer, a paper coil, and a lower spacer. Fabricate and place the lower end coil of the coil, install a hard paper tube on the winding mold, and the hard paper tube is sleeved on the upper surface of the inner diameter edge position of the lower end coil of the coil. Bond and hang spacer braces on the outer circumference of the hard paper tube;

[0045] Step 2. Wind a continuous turn structure with paper-covered flat conductors on the outer circumference of the hanging spacer braces;

[0046] Step 3. Install oil duct spacers between the conductors of the turn structure to form the coil body;

[0047] Step 4. Insulate the conductor leads, place coil outer braces, and tie and fix them along the circumferential direction of the coil with PET tape;

[0048] Step 5. Place screen - oil duct brace - screen - oil duct brace on the outer circumference of the coil outer braces, and fix them along the circumferential direction with white cloth tape to fabricate the valve side coil and the line side coil; the structures of the valve side coil and the line side coil are the same, and the difference lies in the number of screen - oil duct brace - screen - oil duct brace;

[0049] Step 6. The bottom end coil is sleeved on the outer circumference of the iron core, and the valve side coil and the line side coil are arranged in sequence from the inside to the outside starting from the iron core. The valve side coil and the line side coil are hoisted and placed on the bottom end coil to form the coil structure of the test platform.

[0050] In the embodiments of the present invention, the technical features not described in detail are all prior art or conventional technical means, and will not be elaborated here.

[0051] Finally, it should be noted that: the above embodiments are only specific embodiments of the present invention, used to illustrate the technical solutions of the present invention, rather than limiting it. The protection scope of the present invention is not limited thereto. Those skilled in the art should understand that: any person skilled in the art within the technical scope disclosed by the present invention can modify the technical solutions recorded in the foregoing embodiments, or can easily think of changes, or perform equivalent replacements on some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the protection scope of the present invention.

Claims

1. A coil structure of a test platform, the test platform being applied to a converter transformer, characterized in that, The coil structure includes: a bottom end coil (1), a valve side coil (3), and a line side coil (4). The bottom end coil (1), the valve side coil (3), and the line side coil (4) are all sleeved on the outer periphery of an iron core (2). The valve side coil (3) and the line side coil (4) are placed on the upper surface of the bottom end coil (1), and the valve side coil (3) is sleeved between the iron core (2) and the line side coil (4); the valve side coil (3) and the line side coil (4) have the same structure, and both the valve side coil (3) and the line side coil (4) include a coil lower end coil (14) placed at the lower bottom end. Both the valve side coil (3) and the line side coil (4) further include: hanging pad support bars (7) and a hard paper tube (6). The hard paper tube (6) is used to be sleeved and fixed on the outer periphery of a winding mold (5), and the lower end of the hard paper tube (6) is located at the inner diameter edge position of the upper surface of the coil lower end coil (14). A number of hanging pad support bars (7) are fixedly installed at intervals on the outer periphery of the hard paper tube (6) away from the winding mold (5). A lower end coil of the wire (18) is sleeved on the outer periphery of the lower part of the hanging pad support bar (7). The lower end coil of the wire (18) is located on the upper surface of the coil lower end coil (14). A number of oil duct pads (10) are fixedly installed on the upper surface of the lower end coil of the wire (18) to form a bottom layer oil duct pad circle. Above the bottom layer oil duct pad circle, a multi-layer paper-covered flat wire (9) is wound around the outer periphery of the hanging pad support bar (7). A number of oil duct pads (10) are fixedly arranged between any two adjacent layers of the paper-covered flat wire (9). A number of oil duct pads (10) are fixedly installed on the upper surface of the top layer paper-covered flat wire (9) to form a top layer oil duct pad circle. An upper end coil of the wire (8) is sleeved on the outer periphery of the upper part of the hanging pad support bar (7). The upper end coil of the wire (8) is located on the upper surface of the top layer oil duct pad circle.

2. The coil structure of a test platform according to claim 1, characterized in that Both the valve side coil (3) and the line side coil (4) further include: a number of coil outer support bars (11), as well as a number of layers of shielding screens (12) and oil duct support bars (13). The coil outer support bars (11) are fixedly installed on the outer peripheries of the upper end coil of the wire (8), the multi-layer paper-covered flat wire (9), the multi-layer oil duct pads (10), and the lower end coil of the wire (18). A number of layers of shielding screens (12) and oil duct support bars (13) are sleeved on the outer periphery of a circle of coil outer support bars (11). The lower ends of the shielding screens (12) and the oil duct support bars (13) are located on the upper surface of the coil lower end coil (14).

3. The coil structure of a test platform according to claim 2, characterized in that, The coil lower end coil (14) includes an upper pad (15), a paper ring (16), and a lower pad (17). The upper pad (15) and the lower pad (17) are aligned and adhesively bonded to the upper surface and the lower surface of the paper ring (16) respectively.

4. The coil structure of a test platform according to claim 3, characterized in that, The outer perimeters of the upper end coil of the wire (8) and the lower end coil of the wire (18) are provided with first slots. A vertical through hole is opened in the height direction of the coil lower end coil (14). Second slots are provided at intervals along the width direction of the coil outer support bar (11) on the coil outer support bar (11). A PET tape passes through the second slots and binds the coil outer support bar (11) in the circumferential direction.

5. The coil structure of a test platform according to claim 3, characterized in that The cross-section of the hanging cushion strip (7) is T-shaped, and the edges are rounded; the radial cross-section of the upper end ring (8) and the lower end ring (18) of the wire is a rectangular cross-section, and the edges are rounded.

6. The coil structure of a test platform according to claim 3, characterized in that The transverse cross-section of the oil duct strip (13) is a rectangular cross-section, and the corners of the rectangle are rounded.

7. A coil structure of a test platform according to any one of claims 3-6, characterized in that, The materials of the hard paper tube (6), the shielding screen (12), the hanging cushion strip (7), the coil outer strip (11) and the oil duct strip (13) are insulating cardboard.

8. A coil structure of a test platform according to any one of claims 3-6, characterized in that The materials of the upper end ring (8) and the lower end ring (18) of the wire are laminated cardboard.

9. The coil structure of a test platform according to any one of claims 3-6, characterized in that, The materials of the upper cushion block (15), the paper ring (16) and the lower cushion block (17) are laminated cardboard, and the edges of the upper cushion block (15) and the lower cushion block (17) are rounded.

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